1. Field of the Invention
The present invention relates to the field of underwater and harsh environment electrical and fiber-optic connectors. More particularly, the present invention relates to underwater-mateable connectors suitable for high pressure applications.
2. Description of Related Art
An ever increasing need exists for electrical, fiber-optic, and hybrid electro-optical connectors that can be used in hostile environments. Further, a need often exists for such connectors that can be installed in the field and mated/demated repeatedly underwater. As a result, conventional electrical and optical connectors have been developed that can be thus employed, examples of which are found in U.S. Pat. Nos. 4,682,848; 4,411,491; 4,948,377; and 5,194,012.
While the connectors exemplified by these patents do provide interconnection means suitable for harsh environments and that can be cycled underwater, they have many shortcomings. The connectors of the above cited patents employ fluid-filled and pressure-balanced construction, which is a desirable feature. Yet the key to successful operation of connectors of the fluid-filled type is employing the sealing means to keep the fill-fluid in the connector and to keep the outside environment from contaminating the interior of the connector.
Conventional sealing mechanisms exist for accomplishing these functions. One class of such electrical connectors employs an assembly of springs and stoppers to seal the entrance to the mating area of the connectors. While these are successful for electrical connectors, they are not easily adapted to accommodate the connection of optical circuits. Moreover, they are relatively complicated and expensive in both electrical and optical applications.
Another sealing mechanism has an opening into the mating chamber consisting of an elastomeric tubular entrance surrounded by an elastomeric sphincter that pinches the entrance closed either upon itself, in the unmated condition, or against an entering probe, in the mated condition. This has been used with some success for both electrical and optical connectors, but is far from a complete solution to the problem. One drawback is that seals of this sort do not work well in all conditions. Another disadvantage of is that after being mated for a prolonged period of time, such seals lose their "memory," failing to close quickly, and thereby exposing the interior of the chamber to the outside environment.
Still another category of wet-mateable optical connectors uses a simple slit in an elastomeric barrier into the mating chamber of the connector to separate the interior of the chamber from the exterior environment. These connectors rely on the elastic properties of the barrier to seal the connector before, during, and after penetration of the mating probe. They do not work well, however, due to the fact that the seal does not close upon itself reliably. Fill fluid leaks out, and the outside fluid leaks in.
All of the known schemes for providing repeatable, reliable optical connections in hostile environments, therefore, are only marginally effective. The optical connectors presently available are extremely expensive and generally require complicated means for terminating the connector elements to the optical or electrical cables they are intended to eventually connect. While the reliability of electrical connectors is better, the most successful electrical connectors, those employing springs and stoppers for their seal, are complicated, expensive, and not easily adaptable for fiber-optic connections.
Therefore, a need exists for a simple, inexpensive, and effective connector for repeatedly and reliably making either electrical, optical, or hybrid electro-optical connections in hostile environments. Such environments include sea water and high pressure zones, such as the greatest ocean depths.